负载型Cu/TiO₂系催化剂的研究

【作者】 王美涵；

【导师】 辛勤； 徐杰； 周焕文；

【作者基本信息】 辽宁师范大学 ， 物理化学， 2002， 硕士

【摘要】 金属铜和载体TiO₂组成的铜钛系催化剂已经在CO-NO、CO₂加氢等反应中获得应用。由于TiO₂晶型多变，与铜产生相互作用构成协同催化，使其在催化反应过程中与SiO₂、Al₂O₃等载体的作用不同，可影响催化剂的催化性能。早已发现金属铜对加氢反应具有活性，随着催化学科的发展，控制反应的选择性变得越来越重要，实现选择加氢可提高资源的利用程度，降低生产成本。本文以糠醛选择加氢和乙烯氢甲酰化反应为对象，对Cu／TiO₂系催化剂的催化性能进行了研究，以实现环境友好绿色过程，取代含铬糠醛加氢催化剂和乙烯氢甲酰化反应中铑系等贵金属催化剂。主要取得了以下重要结果： 1、在常压条件下进行了糠醛的气相加氢反应，讨论了铜含量、反应温度、氢醛比、助剂对糠醛加氢活性和选择性的影响。结果发现在反应温度160℃，液体空速0.47h^-1，氢醛比为8的条件下，CuO-K₂O／TiO₂催化剂上糠醛的转化率为98.1％，糠醇的选择性为99.9％，与进口Cu-Cr催化剂具有基本相同的活性和选择性。 2、第二种纽份金属Ni的加入改变Cu／TiO₂催化剂在糠醛加氢和乙烯氢甲酰化两个反应中的活性和选择性。随铜镍比的改变，镍相对含量高的催化剂加氢能力强，而铜相对含量高的催化剂有利于氢甲酰化反应。 3、运用TPR、XRD、XPS、BET比表面等方法对Cu／TiO₂系催化剂的物理化学性质进行了表征。BET比表面结果显示，TiO₂负载CuO后，比表面积降低；而负载NiO后其比表面积增加。TPR实验结果表明，Cu与TiO₂、Cu与Ni之间都存在着相互作用。XPS分析表明，助剂K在还原之后，在催化剂表面富集，从而提高了催化剂的活性和选择性。不同铜镍比对催化剂性能的影响是由于铜和镍在催化剂表面上存在的状态和数量不同。更多还原

【Abstract】 TiO2-supported Cu catalyst had been used in CO-NO,CO2 hydrogenation, etc. TiO2 commonly exists in two crystalline forms and there are interaction between Cu and TiO2, which makes TiO2 difference from SiO: and A12O3 as supporter. TiO2 has the effects on the performance of the catalyst. It is well known that metal Cu has good performance in hydrogenation reactions. With the development of catalyst science , the selectivity of the catalyst becomes more and more important. Realizing partial hydrogenation can make full use of the resources. In this paper, the performance Cu/TiO; samples were studied in order to realize well-environment process in hydrogenation of furfural to furfuryl alcohol and use non-noble metal to replace noble metal in ethene hydroformylation to propanal. The following important results were obtained:1. Gas phase hydrogenation of furfural was investigated under atmospheric pressure on Cu/TiO2 catalyst. Effects of different reaction conditions, Cu contents and promoters on the activity and selectivity of the catalyst were discussed. Results showed that the conversion of furfural was more than 98% and the selectivity of furfuryl alcohol was more than 99% over the potassium-promoted catalyst at 160癈, H2/furfural ratio as 1:8.The activity and selectivity of Cu-K/TiO2 catalyst are approximately as the same as Cu-Cr catalyst.2. Adding the second component Ni alternated the performance of Cu/TiO2 catalyst. With the variation of Cu/Ni, the catalyst with high Ni raletive content had the strong ability of hydrogenation, while the catalyst with high Cu raletive content was in favor of ethene hydroformylation reaction.3. Physicochemical property of catalyst had been studied by TPR,XRD,XPS and BET. The results of BET indicated that Ti02 surface area decreased after supporting Cu, but increasedafter supporting Ni. TPR determination showed that there were interactions between Cu and TiO2 or Cu and Ni. The analysis of XPS indicated that K was rich on the surface of the catalyst after reduced, so it increased the activity and selectivity of the catalyst. Effect of variation of Cu/Ni on the catalyst was due to the different states and quantities of Cu and Ni on the catalyst furface.更多还原